The fabrication of bubble generator with high micro-nano bubble generation efficiency has always been challenging. Strong turbulence is considered to be beneficial. Herein, we developed a swirl-type micro-nano bubble generator by equipping a variable-pitch spiral cavitation reactor to enhance the shear breakage effect of bubbles. The variable-pitch spiral guide vanes and central column were innovatively installed into the cavitation reactor to generate swirling liquid flow so as to intensify gas-liquid contacting and mixing. The effect of geometric parameters on the flow field structure was investigated through numerical simulations and the optimum structure was obtained. Then the lab-scale swirl-type micro-nano bubble generator was manufactured to conduct flow tests. The bubbles with size down to 0.301 μm were generated. In addition, the bubble generator displayed superior oxygen enrichment capacity, which was higher than that of the traditional venturi tube. The insights from this study provide a guideline for the development of efficient micro-nano bubble generators.

制造具有高微纳米气泡产生效率的气泡发生器一直具有挑战性。强烈的湍流被认为是有益的。在此，我们开发了一种涡流式微纳米气泡发生器，通过配备变螺距螺旋空化反应器来增强气泡的剪切破碎效果。在空化反应器中创新安装变螺距螺旋导叶和中心柱，产生旋流液流，加强气液接触混合。通过数值模拟研究了几何参数对流场结构的影响，得到了最优结构。然后制造了实验室规模的涡流式微纳气泡发生器进行流动测试。产生了尺寸低至 0.301 μm 的气泡。此外，气泡发生器具有优越的富氧能力，高于传统文丘里管。这项研究的见解为开发高效的微纳米气泡发生器提供了指导。